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A major challenge in influenza research is the selection of an appropriate animal model that accurately reflects the disease and the protective immune response observed in humans. A workshop organised by the EDUFLUVAC consortium, a European Union funded project coordinated by the European Vaccine Initiative, brought together experts from the influenza vaccine community with the aim to discuss the current knowledge and future perspectives for testing broadly reactive influenza vaccines in animal models. The programme included a diversity of models from well-established and publicly accepted models to cutting edge, newly developed animal models as well as ex-vivo approaches and human models. The audience concluded that different vaccine approaches may require evaluation in different animal models, depending on the type of immune response induced by the vaccine. Safety is the main concern for transition to clinical development and influenza vaccine associated enhanced disease was specifically emphasised. An efficient animal model to evaluate this aspect of safety still needs to be identified. Working with animal models requires ethical compliance and consideration of the 3R principles. Development of alternative approaches such as ex-vivo techniques is progressing but is still at an early stage and these methods are not yet suitable for broader application for vaccine evaluation. The human challenge is the ultimate model to assess influenza vaccines. However this model is expensive and not largely applicable. The currently used pre-clinical models are not yet specifically focused on studying unique aspects of a universal influenza vaccine. Further collaboration, communication and effective networking are needed for success in establishment of harmonised and standardised pre-clinical models for evaluation of new influenza vaccines. This report does not provide a complete review of the field but discusses the data presented by the speakers and discussion points raised during the meeting.

The development of broadly reactive influenza vaccines raises the need to identify the most appropriate immunoassays that can be used for the evaluation of so‐called universal influenza vaccines and to explore a path towards the standardisation of such assays. More than fifty experts from the global influenza vaccine research and development field met to initiate such discussion at a workshop co‐organised by the EDUFLUVAC consortium, a European Union funded project coordinated by the European Vaccine Initiative, and the National Institutes of Health/National Institute of Allergy and Infectious Diseases, USA. The workshop audience agreed that it was not possible to establish a single immunoassay for “universal” influenza vaccines because the current approaches differ in the vaccines' nature and immunogenicity properties. Therefore, different scientific rationales for the immunoassay selection are required. To avoid dilution of efforts, the choice of the primary evaluation criteria (eg serological assays or T‐cell assays) should drive the effort of harmonisation. However, at an early phase of clinical development, more efforts on exploratory assessments should be undertaken to better define the immune profile in response to immunisation with new vaccines. The workshop concluded that each laboratory should aim towards validation of the appropriate immunoassays used during the entire process of vaccine development from antigen discovery up to establishment of correlates of protection, including the different steps of quality control (eg potency assays), animal studies and human clinical development. Standardisation of the immunoassays is the ultimate goal, and there is a long way to go.

The deployment of a safe and effective malaria vaccine will be an important tool for the control of malaria and the reduction in malaria deaths. With the launch of the 2030 Malaria Vaccine Technology Roadmap, the malaria community has updated the goals and priorities for the development of such a vaccine and is now paving the way for a second phase of malaria vaccine development. During a workshop in Brussels in November 2014, hosted by the European Vaccine Initiative, key players from the European, North American and African malaria vaccine community discussed European strategies for future malaria vaccine development in the global context. The recommendations of the European malaria community should guide researchers, policy makers and funders of global health research and development in fulfilling the ambitious goals set in the updated Malaria Vaccine Technology Roadmap.

The hepatic hormone hepcidin is a key regulator of systemic iron metabolism. Its expression is largely regulated by 2 signaling pathways: the "iron-regulated" bone morphogenetic protein (BMP) and the inflammatory JAK-STAT pathways. To obtain broader insights into cellular processes that modulate hepcidin transcription and to provide a resource to identify novel genetic modifiers of systemic iron homeostasis, we designed an RNA interference (RNAi) screen that monitors hepcidin promoter activity after the knockdown of 19 599 genes in hepatocarcinoma cells. Interestingly, many of the putative hepcidin activators play roles in signal transduction, inflammation, or transcription, and affect hepcidin transcription through BMP-responsive elements. Furthermore, our work sheds light on new components of the transcriptional machinery that maintain steady-state levels of hepcidin expression and its responses to the BMP- and interleukin-6-triggered signals. Notably, we discover hepcidin suppression mediated via components of Ras/RAF MAPK and mTOR signaling, linking hepcidin transcriptional control to the pathways that respond to mitogen stimulation and nutrient status. Thus using a combination of RNAi screening, reverse phase protein arrays, and small molecules testing, we identify links between the control of systemic iron homeostasis and critical liver processes such as regeneration, response to injury, carcinogenesis, and nutrient metabolism.

BackgroundThe leishmaniases represent a complex of human diseases, with 350 million people at risk of infection worldwide. Although the potential benefits of vaccination have been well-recognised, no human vaccine is registered. Post-kala azar dermal leishmaniasis (PKDL) is a chronic skin disease often following treatment for visceral leishmaniasis (VL). In addition to affecting quality of life, evidence suggests that PKDL patients may also act as reservoirs for VL transmission. Hence, PKDL vaccines may have a significant impact on disease burden. We recently developed a third-generation adenoviral vaccine for leishmaniasis (ChAd63-KH) that has been evaluated for safety and immunogenicity in healthy volunteers (Osman et al,2017). ChAd63-KH is currently being evaluated for safety as a therapeutic in Sudanese PKDL patients, with a phase IIb RCT starting in late 2018. With EDCTP funding, we are initiating a new phase IIa/IIb study (PREV_PKDL) to’determine whether ChAd63-KH can prevent PKDL development.MethodsIn PREV_PKDL, we will conduct an open-label phase IIa safety study, followed by a placebo blinded, phase IIb RCT. Safety and clinical response represent primary outcome measures, and immunogenicity is a secondary outcome measure. In addition, working across the four countries of Leishmaniasis East Africa Platform (LEAP), we will use deep phenotyping methods to study the immune status of patients before and after treatment for VL to understand why PKDL development is limited to specific geographic regions. This work, and other research in the region, will be supported by the creation of a new flow cytometry ‘centre of excellence’ within LEAP.ResultsAn update on the progress of our current therapeutic trial in PKDL patients will be provided.ConclusionPREV_PKDL represents an important step in the clinical development of ChAd63-KH and will help develop capacity to support future vaccine and drug trials for leishmaniasis in the East Africa Region.

International audience; Placental malaria caused by Plasmodium falciparum infection constitutes a major health problem manifesting as severe disease and anaemia in the mother, impaired fetal development, low birth weight or spontaneous abortion. Prevention of placental malaria currently relies on two key strategies that are losing efficacy due to spread of resistance: long-lasting insecticide-treated nets and intermittent preventive treatment during pregnancy. A placental malaria vaccine would be an attractive, cost-effective complement to the existing control tools. Two placental malaria vaccine candidates are currently in Phase Ia/b clinical trials. During two workshops hosted by the European Vaccine Initiative, one in Paris in April 2014 and the other in Brussels in November 2014, the main actors in placental malaria vaccine research discussed the harmonization of clinical development plans and of the immunoassays with a goal to define standards that will allow comparative assessment of different placental malaria vaccine candidates. The recommendations of these workshops should guide researchers and clinicians in the further development of placental malaria vaccines.

IRIDA (iron-refractory iron-deficiency anaemia) is a rare autosomal-recessive disorder hallmarked by hypochromic microcytic anaemia, low transferrin saturation and high levels of the iron-regulated hormone hepcidin. The disease is caused by mutations in the transmembrane serine protease TMPRSS6 (transmembrane protease serine 6) that prevent inactivation of HJV (haemojuvelin), an activator of hepcidin transcription. In the present paper, we describe a patient with IRIDA who carries a novel mutation (Y141C) in the SEA domain of the TMPRSS6 gene. Functional characterization of the TMPRSS6(Y141C) mutant protein in cultured cells showed that it localizes to similar subcellular compartments as wild-type TMPRSS6 and binds HJV, but fails to auto-catalytically activate itself. As a consequence, hepcidin mRNA expression is increased, causing the clinical symptoms observed in this IRIDA patient. The present study provides important mechanistic insight into how TMPRSS6 is activated.

Background Recent global estimates show that P. falciparum malaria still constitutes an enormous public health concern. Chief amongst desirable interventions is an effective vaccine that could complement existing control measures. Heterologous prime-boost vaccinations involving chimpanzee adenovirus 63 (ChAd63) and modified vaccinia Ankara (MVA) encoding ME-TRAP have consistently shown acceptable safety, excellent immunogenicity and substantial efficacy in African adult and paediatric populations. When licensed, malaria vaccines would preferably be given to infants receiving routine childhood immunisations. Nevertheless, no studies have evaluated the interference of ChAd63/MVA ME-TRAP when co-administered with routine Expanded Programme Immunisation (EPI) vaccines. Methods We enrolled 65 Gambian infants and neonates in an age de-escalating fashion, priming at 4 months, 8 weeks or 1 week of age, and randomised them to vaccine or control (EPI vaccines only) arm. Safety was assessed by the description of vaccine-related adverse events ascertained through clinical assessments, biochemical and haematological tests. Immunogenicity was evaluated by IgG ELISA, interferon-gamma ELISPOT, intra-cellular cytokine staining and flow cytometry. Antibody testing was performed to assess any interference of the EPI vaccines with responses to ChAd63/MVA ME-TRAP. Results Overall, the vaccination regimes were well tolerated in all age groups with no vaccine-related serious adverse events. High level IgG and antigen-specific T cell responses were generated after boosting with MVA, with T cell responses highest in the infants 8 week old at priming dose. EPI vaccines retained unchanged antibody levels in all age groups. Conclusions Potent humoral and cellular immunity induced by heterologous prime-boost immunisation with ChAd63 and MVA ME-TRAP did not interfere with the immunogenicity of co-administered routine EPI vaccines in infants and neonates. Potent T cell induction was again observed with the vectored malaria vaccines despite co-administration with EPI vaccines.

Background & Aims The hereditary hemochromatosis-associated membrane proteins HFE, TfR2, and HJV are required for adequate hepatic expression of the iron hormone hepcidin. While the genetic interactions are clear, it remains elusive how bone morphogenetic protein co-receptor HJV functions together with HFE and TfR2 to activate hepcidin transcription via the BMP–SMAD signaling pathway. Here, we investigate whether HFE, TfR2, and HJV physically interact on the surface of hepatocytes. Methods We explore protein–protein interactions by glycerol gradient sedimentation assays and co-immunoprecipitation analyses in transfected HuH7 hepatoma-derived cells. Results Our data demonstrate that HFE and TfR2 bind HJV in a non-competitive manner. Co-immunoprecipitation analyses provide direct experimental evidence that HFE, TfR2, and HJV form a multi-protein membrane complex. Our experiments show that like TfR2, HJV competes with TfR1 for binding to HFE, indicating that the expression of TfR2 and HJV may be critical for iron sensing. We identify residues 120–139 of the TfR2 extra-cellular domain as the critical amino acids required for the binding of both HFE and HJV. Interestingly, RGMA, a central nervous system homolog, can substitute for HJV in the complex and promote hepcidin transcription, implicating RGMA in the local control of hepcidin in the CNS. Conclusions Taken together, our findings provide a biochemical basis for hepcidin control by HFE, TfR2, and HJV.